Athletes, particularly those participating in contact sports often wear a protective device for the mouth that covers the teeth and gums to prevent and reduce injury to the teeth, arches, lips and gums known as a mouth-guard. The device may also be described as a mouth protector, mouth piece, gumshield, gumguard, nightguard, occlusal splint, bite splint, or bite plane. The American Dental Association (ADA) recommends mouth-guards be used in twenty-nine sports: acrobatics, basketball, bicycling, boxing, equestrian, football, gymnastics, handball, ice hockey, inline skating, lacrosse, martial arts, racquetball, rugby football, shot putting, skateboarding, skiing, skydiving, soccer, softball, squash, surfing, volleyball, water polo, weightlifting, and wrestling. Mouth-guards may also be used to prevent or reduce the effects of concussions.